The aging network, renowned for push-to-talk, is finally headed for recycling

In the wee hours of Sunday morning, Sprint Nextel will give its iDEN push-to-talk network the final push -- over the edge.

After more than a year of warnings, the Nextel network will be decommissioned starting at 12:01 a.m. Eastern time Sunday. Sprint will shut down iDEN cells gradually across the country on Sunday, roughly following the time zones from east to west, spokesman Mark Bonavia said.

The iDEN system came from Motorola and formed the basis of Nextel's network, which was begun in 1996. The network ran over spectrum from small regional carriers and frequencies for Motorola's two-way radios. The company built a strong business through its push-to-talk feature, which let users talk to each other instantly without having to first answer a ringing phone. That sounded good to people who worked with their hands, such as plumbers and construction workers.

Sprint saw Nextel's loyal base of blue-collar businesses and the high monthly bills they paid, and in 2005 it merged with the smaller Nextel, creating a company valued at US$35 billion. At the time, Sprint said it would keep investing in iDEN through 2007 and possibly keep using it after that to take advantage of push-to-talk. But as the company struggled with subscriber losses and management changes, it hung on to iDEN.

The system was still renowned for push-to-talk, but it fell behind on speed as 3G and then 4G technologies matured. The iDEN network averages 20K bps (bits per second) to 30K bps.

In May 2012, Sprint finally announced that the system would shut down in June this year. As part of an overhaul of its complicated collection of network technologies, called Network Vision, Sprint will reuse the 800MHz spectrum from iDEN to bolster other services.

Since the announcement last year, Sprint has been alerting Nextel subscribers of the shutdown and working to convert them into Sprint customers. It offers a version of push-to-talk that works over the 3G CDMA network. As of the end of the first quarter in March, the company reported it still had 1.3 million Nextel users.

Though the iDEN network has already been thinned out as part of Network Vision, it's still a working national network until the shutdown begins on Sunday, Bonavia said. He was not able to estimate how many cell sites need to be shut down. The gear can't be reused, but it will be recycled, Bonavia said.

Also heading for the scrap heap is Nextel's name, which Sprint plans to remove from its corporate moniker following its merger with SoftBank, which is expected to close early next month.